Permutation Braid, Two Identical Elements

Pull the slider to form the braid and the list of permutations.
Duplicate permutations are shown in light gray.

Thanks to Bill Mill's idea for this visualization of permutations (http://billmill.org/permvis.html).
The computation is done using either the permutation formula (4!/2!) or the combination formula (C(4,2))(C(2,1)(C(1,1))